1. Field of the Invention
The present invention relates to carbodiimide-containing, hardening type reactive particles, process for producing the same and use of the same, more particularly hardening type reactive particles each comprising a base particle (A) of thermoplastic resin having a functional group and carbodiimide compound (B) impregnated only in the surface layer section or both surface layer section and inside of the base particle, and process for producing the same and use of the same.
2. Description of the Prior Art
Carbodiimides, having a structure of —N═C═N—, have been widely used as a stabilizer for improving hydrolysis resistance for compounds having an ester group or as a crosslinking agent for resins, e.g., (meth)acrylic resin, having carboxyl group reactive with carbodiimide group, where high reactivity of carbodiimide group is generally utilized.
Various applicable areas have been proposed for carbodiimide resins, e.g., paints, adhesives and coating agents, as disclosed by Japanese Patent Application Laid-Open Nos. 10-60272 and 10-30024, and they have been already commercialized in these areas.
However, most of the resins to be crosslinked with a carbodiimide-containing composition are in the form of solution of molten resin, paste or emulsion. Hardening of solid particles themselves requires a great deal of time and is hence difficult.
Production of polyolefin-based resin particles of crosslinked structure by the reaction with a carbodiimide compound in a melting/kneading machine or the like has been studied, as disclosed by, e.g., Japanese Patent Application Laid-Open No. 2000-155441. However, no particles which can sufficiently satisfy resistance to heat and chemicals have been developed.
Broadly speaking, the processes for producing polymer particles fall into two general categories; (I) production of the objective particles by crushing and classifying the resin produced by, e.g., block or solution polymerization, as known, and (II) production of adequate particles during a polymerization stage, e.g., suspension, emulsion or dispersion polymerization, or seed process based on these processes.
Production of hardened particles usually uses a crosslinkable vinyl-based monomer or polymer to improve resistance to heat and chemicals, or incorporate a crosslinkable monomer or polymer other than a vinyl-based one, e.g., epoxy resin or the like, to improve resistance to heat and solvents.